In the scene where Sam fights with a person in the cemetery. The fight scene shows sunlight and shadows in one shot and missing in another. This is repeated while they are wrestling each other on the ground.
When Henry and Dabs are playing Fifa, Henry scores a header - an Xbox 360 logo can clearly be seen in the bottom right corner of the replay screen despite the fact the 2 are playing with PS3 controllers.
In the scene where Sam is talking with the person in the cemetery, while they are sitting side by side on a bench. In one shot there is an object on his left shoulder and it is missing in the next shot.